Chloride channels in myotonia congenita assessed by velocity recovery cycles

Tan, S. Veronica; Z'Graggen, Werner Josef; Boërio, Delphine; Rayan, Dipa Raja; Norwood, Fiona; Ruddy, Deborah; Howard, R.; Hanna, Michael G.; Bostock, Hugh (2014). Chloride channels in myotonia congenita assessed by velocity recovery cycles. Muscle & nerve, 49(6), pp. 845-857. John Wiley & Sons 10.1002/mus.24069

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Introduction: Myotonia congenita (MC) is caused by congenital defects in the muscle chloride channel CLC-1. This study used muscle velocity recovery cycles (MVRCs) to investigate how membrane function is affected. Methods: MVRCs and responses to repetitive stimulation were compared between 18 patients with genetically confirmed MC (13 recessive, 7 dominant) and 30 age-matched normal controls. Results: MC patients exhibited increased early supernormality, but treatment with sodium channel blockers prevented this. After multiple conditioning stimuli, late supernormality was enhanced in all MC patients, indicating delayed repolarization. These abnormalities were similar between the MC subtypes, but recessive patients showed a greater drop in amplitude during repetitive stimulation. Discussion: MVRCs indicate that chloride conductance only becomes important when muscle fibers are depolarized. The differential responses to repetitive stimulation suggest that in dominant MC the affected chloride channels are activated by strong depolarization, consistent with a positive shift of the CLC-1 activation curve. © 2013 Wiley Periodicals, Inc.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurology
04 Faculty of Medicine > Department of Head Organs and Neurology (DKNS) > Clinic of Neurosurgery

UniBE Contributor:

Z'Graggen, Werner Josef; Boërio, Delphine and Bostock, Hugh

Subjects:

600 Technology > 610 Medicine & health

ISSN:

0148-639X

Publisher:

John Wiley & Sons

Language:

English

Submitter:

Nicole Söll

Date Deposited:

03 Apr 2014 08:45

Last Modified:

10 Mar 2015 13:48

Publisher DOI:

10.1002/mus.24069

PubMed ID:

24037712

BORIS DOI:

10.7892/boris.44494

URI:

https://boris.unibe.ch/id/eprint/44494

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